A MODEL OF CARDIAC NOCICEPTION IN CHRONICALLY INSTRUMENTED RATS - BEHAVIORAL AND ELECTROPHYSIOLOGICAL EFFECTS OF PERICARDIAL ADMINISTRATION OF ALGOGENIC SUBSTANCES
A MODEL OF CARDIAC NOCICEPTION IN CHRONICALLY INSTRUMENTED RATS - BEHAVIORAL AND ELECTROPHYSIOLOGICAL EFFECTS OF PERICARDIAL ADMINISTRATION OF ALGOGENIC SUBSTANCES
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DOI：
10.1016/0304-3959(94)90191-0
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发表时间：
1994-07-01
期刊：
影响因子：
7.4
通讯作者：
GEBHART, GF
中科院分区：
文献类型：
--
作者：
EUCHNERWAMSER, I;MELLER, ST;GEBHART, GF
这份报告提供的证据表明，心包给药混合致过敏物质是一种潜在的有用的心脏伤害性感受模型。在至少5天前在心包囊内放置硅胶导管的清醒大鼠，给予等量缓激肽(BK)、乙酰胆碱(ACh)、腺苷(ADEN)、组胺(HIST)、5-羟色胺(5-羟色胺)和前列腺素E(2)(PGE(2))的混合物(25nmol25亩L)可迅速获得被动回避行为。相反，单独给予BK(5-25nmol)或ACh、ADEN、HIST、5-HT和PGE(2)的混合物不加BK，都不能引起行为习得，也不能产生与相同体积的生理盐水(25亩L)心包腔内注射有显著差异的效果。BK和含有BK的混合物均产生类似程度的剂量依赖性心血管反应(压力反应和心动过速)。无论是生理盐水还是不含BK的混合物，平均动脉压或心率都没有明显变化。在同一大鼠的电生理实验中，胸髓神经元对混合物的反应呈剂量依赖性，除一个神经元外，对BK的反应也呈剂量依赖性。然而，与混合物中含有的类似剂量的BK相比，对BK的反应在幅度和持续时间上都明显较小。AH单位接受来自胸部的会聚躯体输入，所有神经元也接受来自食道的会聚输入。食道的气囊扩张使所有单位兴奋。将致过敏物质注入清醒大鼠的心包囊的行为特征的结果证明了BK和包括BK在内的六种物质混合物的作用不同。在所测试的两个剂量中的任何一个剂量的BK产生的效果与生理盐水相同，而含有BK的混合物是令人厌恶的。在互补的电生理研究中，BK和含有BK的混合物都能兴奋胸段脊髓神经元，这表明神经元对可能的致过敏物质的反应不一定是心脏伤害性感受的可靠指标。
This report presents evidence that pericardial administration of a mixture of algogenic substances is a potentially useful model of cardiac nociception. In awake rats in which a looped silicone catheter had been placed in the pericardial sac at least 5 days previous, administration of a mixture containing equal concentrations of bradykinin (BK), acetylcholine (ACh), adenosine (ADEN), histamine (HIST), serotonin (5-HT) and prostaglandin E(2)(PGE(2)) (total 25 nmol in 25 mu l) led to rapid acquisition of a passive avoidance behavior. In contrast, neither BK alone (5-25 nmol) nor the same mixture of ACh, ADEN, HIST, 5-HT and PGE(2) without BK led to acquisition of the behavior or produced effects significantly different than produced by saline given into the pericardial sac in the same volume (25 mu l). Both BK and the mixture containing BK produced dose-dependent cardiovascular responses (presser response and tachycardia) of similar magnitude. Neither saline nor the mixture without BK produced significant changes in mean arterial blood pressure or heart rate. In electrophysiological experiments in the same rats, thoracic spinal cord neurons responded dose-dependently to the mixture and, except for one neuron, responded also to BK in a dose-dependent manner. However, responses to BK, when compared to a similar dosage of BK contained in the mixture, were significantly less in magnitude and duration. AH units received convergent somatic input from the thorax and all neurons also received convergent input from the esophagus. Balloon distension of the esophagus excited all units. Results of the behavioral characterization of algogenic substances administered into the pericardial sac of awake rats gave evidence of differences between the effects of BK and a mixture of six substances, including BK. BK in either of two dosages tested produced effects not different than saline while the mixture containing BK was aversive. In complementary electrophysiological studies, both BK and the mixture containing BK excited thoracic spinal cord neurons, suggesting that neuron responses to putative algogenic substances are not necessarily reliable measures of cardiac nociception.